Efforts to reduce smoking and improve health are being hampered by the black market trade of millions of illegal cigarettes filled with excrement, dead flies and asbestos, local authority leaders have warned.
The Local Government Association (LGA) said fake cigarettes also pose a fire risk, damage honest businesses and cost the UK economy around £3 billion a year in unpaid duty.
Recent council efforts to crack down on the illicit trade have led to the seizure of hundreds of thousands of illegal cigarettes in Wolverhampton, Bristol and Nottingham.
Sniffer dogs were deployed in Birmingham during raids on 12 premises across the city.
Meanwhile Southwark, Bexley, Bromley, Greenwich, Lambeth and Lewisham councils have formed a partnership to tackle the black market trade of 114 million illicit cigarettes which are estimated to be sold in the area each year.
Trading standards officers have found fake cigarettes hidden inside vacuum cleaners, under floorboards and in toilet cisterns.
Some have contained asbestos, mould, dust, dead flies, rat droppings and human excrement. Many feature much higher levels of toxic ingredients such as tar, nicotine, carbon monoxide, lead, cadmium and arsenic than genuine cigarettes.
Fake cigarettes also pose an increased fire risk as they do not include designs that ensure that, once lit, a cigarette will self-extinguish if it is not actively smoked. This reduces the chances of them starting a fire if they are left burning in an ashtray, dropped or if the smoker falls asleep.
Councillor Joanna Spicer, vice chair of the LGA's safer and stronger communities board, said: " Counterfeit tobacco being sold cheaply through the black market by rogue traders is hampering council efforts to reduce smoking. This illicit trade is also funding organised criminal gangs, damaging the livelihoods of honest businesses and costing taxpayers billions of pounds a year.
"People buying cheap cigarettes might think they are getting a great deal - but the truth is that they're not. If they knew what they might contain, they might think twice about buying them.
"Council prosecutions should serve as a strong warning to any shopkeeper thinking of stocking their shelves with illegal tobacco and not thinking twice about selling them cheaply to children and others."